1. Field of the Present Invention
The present invention relates generally to electrical test leads, and in particular, to test leads that allow physical and electrical contact of test instruments to a device under test using a magnetic probe to connect to the device.
2. Background
Electricians, automotive technicians and other personnel are frequently required to use various test instruments to test electrical equipment and systems such as circuit panels, power supplies (including car batteries), automotive electronics, and the like. The test instruments may include digital multimeters, phase meters, oscilloscopes, and the like. Conventionally, testing the equipment requires connecting test leads to the test instrument and then establishing electrical contact between the opposite ends of the test leads and appropriate test points on the equipment under test. For this purpose, each test lead typically includes a first suitable electrical connector for connecting the lead to the test instrument and a second suitable electrical connector for making electrical contact with the test points on the equipment under test. Both electrical connectors are generally of conventional construction, with the first electrical connector often being a plug-type connector, such as a banana-type connector, and the second electrical connector being a test probe, a clip (such as an alligator clip or any of various other types of clips suitable for temporary attachment to the test point), or the like.
Often, the electrician, technician or other tester must hold the test instrument in one hand while he manipulates one of the test probes with his other hand, thus preventing him from carrying out any other activities (since both hands are occupied). Clip-type connectors may free one hand, but require a suitable attachment point in order to work.
Another issue faced by electricians and other testers is the frequent presence of potentially lethal voltages and currents that are present in and around the equipment under test. When using the test probes, or when trying to attach a clip to the equipment under test, the user thus faces the prospect of an electrical shock or even electrocution.
Thus, a need exists for a more convenient and potentially safer type of test lead that allows the operator to couple his test lead from his test instrument to a common (possibly ground) point on the equipment under test during the entire troubleshooting or other test exercise, with no other intervention from the operator except the initial placement of the electrical connector.